I am a 21 years old woman and have been seeing a guy of my age. We have rather been seeing each other as friends and spending good times together. We kiss when me meet and even though the kisses are really affectionate as they appear to me, I sense his erection while we're hugging tight and sharing a kiss, often just a peck. I wonder what he thinks or feels while kissing me. Is it natural and to all men or does it happen when a man gets occupied with other thoughts during the kiss?